Flow Metrology for Liquefied Natural Gas (LNG)

Transcription

1 Flow Metrology for Liquefied Natural Gas (LNG) EMRP Project Introduction and overview October 2011 Lars Poder, FORCE Technology

2 About LNG Liquefied Natural Gas is produced by cooling down natural gas below its dew point (-161 C) A unique solution for transporting natural gas to areas far from a pipeline structure The volume occupied by LNG at atmospheric pressure is about 614 times smaller than its gaseous state this reduces the space needed to freight an amount of energy LNG is shipped in carriers from liquefaction plants to large tanks in buyer countries These wessels can load from 145,000 to more than 200,000 m 3 The energy volume of such a consignment corresponds to TWh One LNG cargo represents the annual power consumption of roughly 200,000 households in Denmark.

3 LNG process Liquefaction Shipping Regasification Loss: 8 10 % 1 4 % 1 2 % 1% = 440 M /year in 2010 and 900 M /year in 2015

4 LNG globalt % af total Største importører Japan 38% Korea 17% Spanien 13% Frankrig 6% Taiwan 4% Største eksportører Qatar 17% Malaysia 13% Indonesien 12% Algeriet 11% Nigeria 9%

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6 DONG Energy øger naturgas aktiviteterne i Nordvesteuropa

7 DONG Energy s adgang til LNG: Gate Terminal Fakta om Gate Terminal Lokaliseret i Rotterdam havn Start up lagertanke á m3 Samlet kapacitet: 12 mia. m3 om året Ca. 180 skibe om året ved fuld udnyttelse Samlet investering: 950 mio. Firma Ejerandel [%] Kapacitetsandel [mia. m 3 ] Vopak 40 Gasunie 40 DONG Energy 5 3 E.ON 5 3 OMV 5 3 RWE 5 3

8 The project s overall objective To contribute to a significant reduction of uncertainty (by at least a factor two) in the determination of transferred energy in LNG custody transfer processes (1% uncertainty = 440 M /year in 2010 and 900 M /year in 2015) Contribute to: Improving existing methods Validating new methods Creation of new calibration systems with improved uncertainty International technical and legal standards and guidelines

9 Project aims and objectives Volume Mass Density Gross Calorific Value Developing traceability for LNG (mass and volume) flow meters (WP1) Testing and evaluating LNG quantity metering systems (WP2) Improving LNG composition measurement systems (WP3) Reducing uncertainties in LNG density calculations (WP4) Improving LNG composition measurement systems (WP3) Reducing uncertainties in LNG density calculations (WP4) WP5 Measurement Guidelines Written Standards Legal Metrology Energy Energy = Volume x Density x Gross Calorific Value

10 WP1 Developing traceability for LNG flow meters Developing of a primary LNG mass flow standard (25 m 3 /h, target uncertainty 0.05%) Uncertainty assessment upscaling method Developing simulation upscaling method Developing mid-scale flow standard / first stage upscaling standard (200 m 3 /h, target uncertainty 0.07%) Comparing water, LN2 and LNG calibrations Defining economic calibration concept Studying technical feasibility and uncertainty of laser doppler velocimetry for LNG flow measurement

11 Developing a primary LNG mass flow standard Flow rate: Q = 5-25 m 3 /h LIN and LNG (testing with LIN) Operation pressure: p = 3-4 bar(g) Operation temperature: T = -160 C (-195 C for LIN) Uncertainty target < 0.05% Lower uncertainty than LN2 NIST facility (0.17 %) Uncertainty VSL water facilities 0.02 %

12 Kalibrering af flowmåler med LIN - hvordan? Temperatur: -195 C Diameter: 2 Flow range: l/min Tryk: 2 3 bar

13 Kalibrering af flowmåler med LIN - mod hvad? Master Meter: Hoffer HO11/2X11/ CB-1M-1S S/N: ID#: TE-635 Calibration Date and place: at NIST (US)

14 Test af flowmåler med LIN hvilke(n) måler(e)? Coriolis Vortex Turbine Kølehals Accuracy + - Pressure loss + + Price - +

15 WP2 Testing and evaluating LNG quantity metering systems Evaluating uncertainty of shiptank based measurement systems Field testing: Comparing static (tank level) and dynamic (flow metering) quantity metering systems Studying (simulation and experiments) effect of cryogenic media on measuring system (flow meter, tempertaure and pressure sensors) Studying (simulation and experiments) of installation effects on LNG flow meters

16 Static versus dynamic volume measurements Typically Level gauging + gauge table (static) Uncertainty: %? Alternative Volume rate meters (dynamic) Uncertainty: %? No direct traceable link to SI units Calibration facility required!

17 , Flow Metrology for LNG Introduction This study is part of the EMRP project Metrology for Liquefied Natural Gas (LNG) [17] and focuses on the uncertainty of static LNG volume measurements as encountered in (un)loading LNG ships. For the uncertainty in the (un)loaded LNG volume one usually refers to the LNG custody transfer handbook of G.I.I.G.N.L. [16], in which a value of 0.42% is claimed (level of confidence of 95%, see Section 15.5). However, the LNG custody transfer handbook is not a standard but a document providing guidance to the industry by describing common practice. It can, therefore, not be used as a norm or standard. In addition, a thorough uncertainty assessment is lacking in the view of the authors. For example, several uncertainty contributions have not been validated and covariance s are not accounted for in the combination of uncertainty sources. As of yet a thorough metrologically sound uncertainty budget has not been conducted, probably because LNG shipping is typically bound by long-term contracts. Furthermore, buyers and sellers see uncertainty as inherent to level gauging. Conclusions The present report summarizes the formulas used to determine the uncertainty associated with the LNG volume transferred to or from a ship. The results are applicable to both Moss type and Membrane type tanks. Unlike other uncertainty estimations that can be found in the literature, the one presented in this work is fully in accordance with the GUM and it includes real shipment data. The shipment data indicates that the uncertainty in level gauging is higher, potentially much higher, than stated elsewhere. For a Membrane type tank, for example, the total uncertainty is significantly higher than stated in the GIIGNL LNG custody transfer handbook. In case the differences in level gauging equipment are taken into account, the uncertainty is close to 1 %. The largest uncertainty contribution comes from the main gauge table, while it is unsure what the coverage factor is. Uncertainty contributions from trim and list are essential for terminals that are poorly protected from or are at open sea.

18 WP5 Contributing to measurement guidelines, written standards and legal metrology Providing input to ISO and CEN standardization (ISO TC28/SC5, ISO 10976, ISO , ISO TC67/WG10, ISO TC193, ISO 6976, CEN TC282, EN ) Providing information/guidelines to EURAMET TC-Flow Providing input to legal metrology (MID/OIML) Providing input to GIIGNL (custody transfer handbook) and LNG industry (Groupe International des Importateurs de Gaz Naturel Liquéfié)

19 Project duration: May 2010 May 2013 Project coordinator: Ir. Oswin Kerkhof, VSL Funding: Approx. 3 M (46% EU/EMRP, 54% Metrology organisations) Project partners: VSL, Netherlands SP, Sweden TUV NEL, United Kingdom FORCE Technology, Denmark Justervesenet, Norway CMI, Czech Republic Cesame, France INRiM, Italy PTB, Germany ENAGAS, Spain ELENGY, France E.ON RUHRGAS, Germany

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